We have studied the use of the long-acting somatostatin analogue, SMS 201-995, in acromegaly, TSH secreting pituitary tumors and glucagonomas. These studies have defined 1) an appropriate dose and schedule for control of TSH secretion from TSH secreting pituitary adenoma and its resultant hyperthyroidism, 2) an appropriate subgroup of acromegaly patients in whom this analogue, given thrice daily, controls GH hypersection, 3) the effects of the drug in glucagonoma syndrome in terms of control of glucagon hypersecretion and correction of hypoaminoacidemia. We are proceeding with long-term therapy of patients with the analogue to study effectiveness and side effects.